3.2.2.28 <param>

The <param> (parameter) element specifies a set of values that might be required by an <object> at runtime.
Any number of <param> elements might
appear in the content of an <object> in any order, but must be placed at
the start of the content of the enclosing object. This element is comparable to the XHMTL
<param> element, and its attributes' semantics derive from their HTML
definitions. For example, the @type attribute differs from the
@type attribute on many other DITA elements.

Content models

See appendix for information about this element in OASIS document type shells.

Example

Attributes

Specifies the value of a run-time parameter that is specified by the @name
attribute.

@valuetype

Specifies the type of the @value attribute. Allowed values are:

data

A value of data means that the value will be evaluated and passed to the
object's implementation as a string.

ref

A value of ref indicates that the value of the @value attribute
is a URL that designates a resource where run-time values are stored. This allows
support tools to identify URLs that are given as parameters.

object

A value of object indicates that the value of @valuetype is an
identifier that refers to an object declaration in the document. The identifier
must be the value of the ID attribute set for the declared object element.

This attribute specifies for a user agent the type of values that will be found at the URI
designated by @value. Note that this differs from the @type
attribute on many other DITA elements.

When @valuetype is set to "ref", this attribute directly specifies
the content type of the resource designated by @value.

Otherwise, if @type is specified
and @keyref is specified and resolvable, this attribute specifies
the content type of the resource designated by @keyref.

Otherwise, if @type is not
specified and @keyref is specified and is resolvable, the
effective type value specified for the key that is named by the
@keyref attribute is used as the value of the
@type attribute.

@keyref

Key reference to the thing the parameter references. If @valuetype is
specified but is not set to "ref", this attribute is ignored. When
@valuetype is not specified and @keyref is specified,
it implies a setting of valuetype="ref". When @keyref
is specified and the effective value of @valuetype is "ref":

When the key specified by @keyref is resolvable and has an
associated URI, that URI is used as the value of this element (overriding
@value, if that is specified).

When the key specified by @keyref is resolvable and has no
associated resource (only link text), the @keyref attribute
is considered to be unresolvable for this element. If @value is
specified, it is used as fallback.

When the key specified by @keyref is not resolvable, the value of
the @value attribute is used as a fallback target for the
<param> element.